<?php
$css=array(
	'1.css',
	'2.css'
);

?>
<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<link rel="stylesheet" href="<?php echo $css[mt_rand(0,1)];?>">
</head>
<body>
	<?php echo $css[mt_rand(0,1)];?>
</body>
</html>